Understanding the structure and properties of geological formations can reduce the cost of drilling wells for oil and gas exploration. Measurements made in a borehole (i.e., down hole measurements) are typically performed to attain this understanding, to identify the composition and distribution of material that surrounds the measurement device down hole. A variety of devices may be used to make such measurements, including transducers. For example, compressional wave velocity measurements can be made using ultrasound transducers, and resistivity measurements can be made using antennas. Sometimes power must be applied in a controlled manner to these transducers, to improve the accuracy of the resulting measurements.